Flow meter having vertical rotor shafts

ABSTRACT

A flow meter has vertically disposed rotor shafts which rotate integrally with rotors responsive to the flow quantity of a fluid. The shafts are supported, on one hand, by thrust bearings which pivotally receive vertical shaft loads due to the weights of the rotors and shafts and supported, on the other hand, by radial bearings which receive transverse shaft loads due to the rotation of the rotors and the shafts caused by the differential pressure of the fluid. The rotors and the shafts receive an upwardly acting force due to the differential pressure between inlet and outlet passages, and whereby the vertical shaft loads due to their weights are reduced.

United StateS Patent [191' Irie et al.

m] 3,748,903 [451 July 31,1973

154] FLOW METER HAVING VERTICAL ROTOR SHAFTS [75] Inventors: Yoshihlkolrie, Kawasaki; Mahiko Kato, Tokyo; Kiyondo Gomi', Yokohama, all ofJapan [73] Assignee: Tokico Ltd., Kawasaki-City, Japan [22] Filed: Aug.4, 1971 [21] Appl. No.: 168,829

[30] Foreign Application Priority Data 1,996,672 4/1935 Busch l 73/2613,110,525 11/1963 Sternlight 308/9 3,121,330 2/1964 Leslie et al. 309/9Primary Examiner-Herbert Goldstein Attorney-Eric H. Waters et al.

[57] ABSTRACT A ow meter has vertically disposed rotor shafts whichrotate integrally with rotors lresponsive to the flow quantity of afluid. The shafts are supported, on one hand, by thrust bearings whichpivotally receive vertical shaft loads due to the weights of the rotorsand shafts and supported, on the other hand, by radial bearings whichreceive transverse shaft loads' due tov the'rotation of the rotors andthe shafts caused by the differential pressure of the fluid. The rotorsand the vshafts receive an upwardly acting force due to the differentialpressure between inlet and outlet passages, and whereby the verticalshaft loads due to their weights are reduced.

5 Claims, 6 Drawing Figures 'PAIENIEUJULS 1 |913 SHEET 0F 4 FIG. 3

- FLow QUANTITY PATENEUJULN |975 3. 748.903

snm a of a FIG. 4

T o F- i60 Wb! f7 Av/5 l 2o gil @2l 59 7 /4 i f 'm FLOW METER HAVINGVERTICAL ROTOR SHAFTS Accordingly, the quantity of leakage from betweenthe rotors and the inner housing has an influence on the value ofinstrumental error. If this quantity 'of leakage is small, an accuratemeasurement can be achieved even when the flow quantity is low.Therefore, in order to improve the instrumental error in the low flowquantity, the quantity of leakage should be reduced to the minimum. Forthis purpose, it is important that rotational resistance of the rotorsduring their rotations should be minimized.

In a conventional positive displacement type flow meter, rotor shaftswhich rotate integrally with the rotors are arranged horizontally sothat sliding resistance between the side surfaces of the rotors and theside plates in the casing will be reduced. The following method havebeen adopted to improve the instrumental error in the low flow quantityof this conventional flow meter having the horizontal shafts: (1) Thegap between the rotors and the inner housings are made as small aspossible. (2) The rotational resistance which the rotor receivesis'reduced by employing a light alloy such as aluminum alloy as thematerial for the rotors so as to reduce a bearing load or by employingball bearings as the bearings for the rotors so as to reduce rotationalresistance of the bearings.

It is generally observed that there are usually some scales in fluid,which scales cannot be completely removed by a streiner. Accordingly,the conventional flow meter in which the above described method (l) isadopted is disadvantageous in that the extremely small gap between therotors and the inner housings causes the scales to block the gapsbetween the rotors and the inner housings, thereby making the rotationof the rotors unstable and injuring the side surfaces of both rotors andthe inner housings resulting in decrease in the durability of the flowmeter. The conventional flow meter in which the above described method(2) is adopted is also disadvantageous in that if a light alloy such asaluminum alloy is used as the material of the rotors, the flow metercannot be used lfor measuring a corrosive fluid such as a chemical agentbecause the rotors will be corroded by the fluid. The kinds of fluidswhich can be measured by such flow meter are therefore limited.Furthermore, if ordinary ball bearings made of steel are used as thebearings for the shafts, the ball bearings are worn away in a relativelyshort period due to their engagement with the scales. Moreover, theseball bearings cannot be used for corrosive fluids.

The conventional horizontal type flow meter has the rotor shaftsdisposed horizontally and journalled by the horizontal radial bearingsat positions adjacent to both ends thereof. Due to this construction,the bearings receive a shaft load applied by the shafts when the rotorsare rotated by the differential pressure of the fluid in addition to aload applied due to weights of the rotors and the shafts. As a result,the bearings are worn on one side only and therefore wear repidly andtheir life is relatively short. This will present a serious problemparticularly in the case wherein the fluid to be measured is one whichis poor in a lubricative nature.

It is, therefore, a general object of the invention to provide a noveland useful flow meter eliminating the above described disadvantages ofthe conventional horizontal type flow meter.

Another object of the invention is to provide a vertical type flow meterin which rotor shafts rotating integrally with rotors are disposedvertically relative to a horizontal plane. According to the verticaltype flow meter made in accordance with the present invention, rotationresistance which the rotors receive during their rotations is so smallthat an accurate measurement of the flow quantity can be achieved evenwhen the quantity to be measured Vis small and the instrumental error isextremely reduced. Accordingly, measurement in a low flow quantity ismade possible, whereby the range in which measurement is practicablypossible is enlarged. The shaft loads applied in a vertical directiondue to the weights of the rotors and the shafts are carried by thrustbearings, whereas the shaft loads in a horizontal direction producedwhen the rotors are rotated by the dierential pressure are carried byradial bearings. Therefore the shaft loads are divided and durability ofthe bearings is improved. Further, due to the vertical arrangement ofthe shafts, a counter section to which rotation of the shaft istransmitted can be mounted on the upper part of the casing of the flowmeter. Accordingly, space can be saved in the piping of the flow meter.

A further object of the invention is to provide a flow meter `havingvertically disposed rotor shafts in which the shaft loads applied in avertical direction due to the weights of the rotors and shafts arereduced by utilizing the differential pressure between the inlet passageside and the outlet passage side of the flow meter. According to thisflow meter, the rotation resistance of the rotor shaft and the bearingis further reduced. The instrumental error in the low flow quantity isfurther reduced and the life of the flow meter is prolonged.

A still further object of the invention is to provide a flow meter whichis possessed with high anticorrossion and antiwearing characteristics byusing a special super hard alloy as the material of the bearings for therotor shafts.

Other objects and features of the invention will become apparent fromthe description made hereinbelow with reference to the accompanyingdrawings, in which:

FIG. 1 is a cross-sectional plan view of one embodiment of the flowmeter according to the invention;

FIG. 2 is a side elevational view of the flow meter taken along the lineII--II of FIG. l partly shown in a vertical section;

FIG. 3 is a cross-sectional plan view of another embodiment of the flowmeter according to the invention;

FIG. 4 is a side elevational view of the flow meter taken along the lineIV-IV of FIG. 3 partly shown in a vertical section;

FIG. 5 is a graphical diagram showing a flow quantity instrumental errorcharacteristic; and

FIG. 6 is a graphical diagram showing a flow quantity differentialpressure characteristic.

The first embodiment of the ow meter according to the invention will bedescribed with reference tov FIGS. l and 2. A flow meter designated byreference numeral l generally consists of a casing 1l and a counter partl2 mounted on the top thereof. On both sides of the casing 1l, there areprovided an inlet passage 13 and an outlet passage 14. An upper innercasing side plate 1S and a lower inner casing side plate 16 are fixedlymounted to the casing l1, vertically spaced apart from each other by apredetermined distance and defining a fluid passage. inner housings 17aand 17h having semicircular sections 18a and 18b respectively are xedlymounted between the upper side plate and the lower side plate 16 withinthe casing 11. lt is to be noted that the flow meter l0 in the presentembodiment is installed and used in a state in which its crosssectionincluding the inlet passage 13 and the outlet passage 14 is in ahorizontal plane.

Rotors 2l and 22 fixed respectively to rotor shafts 19 and are rotatablydisposed within a space defined by the upper side plate 1S, lower sideplate 16 and inner housings 17a and 17b. The upper side plate l5 and thelower side plate 16 are respectively provided with sliding bearings orradial bearings 23, and 24, 26 made of carbon or the like material. Theshafts 19 and 20 are respectively supported by the radial bearings 23,24

and 25, 26 vertically with respect to the horizontal plane and therebyprevented from transverse vibrations.

The lower ends of the shafts 1'9 and 20 are respectively pivotallysupported by thrust bearings 29 and 30 through ball bearings 27 and 28.As the material for the lower portion of the shafJs 19 and 20, ballbearings 27 and 28 and thrust bearings 29 and 30, super hard alloys suchas tungusten carbide and chrome carbide which have high anticorrosionand antiwearing characteristics should preferably be used. A supportmember 31 is fixedly mounted at its upper end to the lower surface ofthe lower side plate 16 and has its lower portion fitted in anopening-of the casing ll in a watertight manner. Bearing assemblies 32and 33 having the thrust bearings 29 and 30 at the upper portionsthereof lare in threaded engagement at their threaded portions 34 and 35with the support member 3l. The bearing assemblies 32 and 33 are in awatertight engagement with the support member 31 and are capable ofsliding vertically slightly relative thereto.

A fluid to be measured enters a chamber 40 formed between the lower sideplate 16 and the support member 3l through the clearances between theshafts 19 and 20 and the radial bearings 24 and 26. Consequently, thebearings 27, 28, 29 and 3,0 are used in the fluid with the result thatfrictional resistance at the bearings is reduced.

Pilot gear wheels 36 and 37 are mounted on the upper end portions of theshafts 19 and 20. The pilot gear wheels 36 and 37 are in meshingengagement with each other, whereby rotors 21 and 22 are rotated inassociation witheach other. A toothed portion 39 xedly mounted on theupper end of the shaft 20 meshes with a gear 38. The rotation of theshafts 19 and 20 are transmitted to the gear 38 and then to a countr inthe counter part l2. lt will be noted that the abovementioned pilot gearwheels are unnecessary if oval gear wheels are used as the rotors.

The operation of the flow meter 10 having the above describedconstruction will be described.

When the fluid to be measured flows into the inlet passage 13, therotors 2l and 22 are rotated due to the differential pressure ofthefluid between the inlet passage 13 and the outlet passage 14. At eachrotation of the rotors 2l and 22, predetermined quantity of the fluid issent out to the outlet passage. The roationsv of the rotors 21 and 22are transmitted to the counter provided in the counter part l2 throughthe shaft 20, the toothed portion 39 and the gear wheel 38, operatingthe counter to make the measuring ofthe flow quantity.

The shafts 19 and 20 are respectively supported by the bearings 23, 24,2S and 26 in a transverse direction and by the bearings 29 and 30 onlyin a vertical direction. The vertical shaft load including the selfweights of the rotor-21 or 22 and the shaft 19 or 20 is carried by thesingle bearing 29 or 30. Further, the insertion of the ball bearings 27and 28 between the lower end portions of the shafts 19 and 20 and thebearings 29 and 30 serves to minimize the areas of the shafts 19 and 20which are in contact with the thrust bearings 29 Vand 30. Accordingly,the frictional resistance which the shafts 19 and 20 receive duringtheir rotations is extremely small. The shaft load carried by thebearings 23, 24, 2S and 26 is only a load applied in a transversedirection due to the differential pressure of the fluid during rotationof the rotors 21 and 22, and not the load including the self weights ofthe rotors-21 and 22 etc. Accordingly, the shaft load is extremelyreduced as compared with the conventional flow meter in which the shaftsof the rotors are horizontally supported.

Due to reduction in the areas of the shafts 19 and 20 which are incontact with the bearings 29 and 30 and accompanying reduction in therotational resistance combined with reduction in the shaft load carriedby the bearings 23 to 26, the shafts 19 and 20 and the rotors 21 and 22can be easily rotated by a small differential pressure. Accordingly, theflow meter according to the invention has eliminated the disadvantagesin the conventional flow meter that the rotors 21' and 22 are notrotated or rotated with difficulty when there is only a smalldifferential pressure between the inlet passage 13 and the outletpassage 14 due to the low flow quantity with the result that the fluidleaks through the gap between the rotors 2l and 22 or the gaps betweenthe rotors `2l, 22 and the inner housings 17a, l7b. Therefore, the flowmeter according to the invention is capable of measuring the flowquantity accurately with a minimum instrumental error particularly whenthe flow. quantity is low, which is an achievement the conventional flowmeter failed to make.

The instrumental error characteristics relative to flow quantity of theconventional flow meter and the flow meter according to the inventionare shown in FIG. S. ln the diagram, the curve A represents the flowquantity instrumental error characteristic of the conventionalhorizontal type flow meter in which the rotor shafts are horizontallyjoumalled. The curve B represents the flow quantity instrumental errorcharacteristic of the flow meter according to the invention in which therotor shafts are vertically arranged. As it will be apparent from thediagram, the instrumental error when the flow quantity is low is largein the conventional flow meter shown by the curve A. Whereas, in theflow meter according to the invention shown by the curve B, theinstrumental error particularly at the low flow quantity is muchimproved compared with the conventional flow meter. Y

Nextly, the second embodiment of the flow meter according to theinvention will be described with reference to FIGS. 3 and 4. ThroughoutFIGS. l to 4, the

same component part is designated by the same reference numeral and thedescription thereof will be omitted.

A flow meter 50 generally consists of a casing 51 and the counter part12. The casing 5l is formed with a passage 53 of a small diameter whichconnects the inlet passage 13 and a lower chamber 52 defined by thecasing 51 and the lower side plate 16. The casing 51 is also formed witha passage 55 of a small diameter which connects the outlet passage 14and an upper chamber 54 defined by the casing Sll and the upper sideplate 15.

A support member 56 having an opening 57 on one side thereof is fixedlymounted at its upper end to the lower surface of the -lower side plate16 and has its lower portion fitted in an opening formed in the casing51 in a watertight manner. A chamber 65 in the support member 56 iscommunicated with the inlet passage 13 through the passage 53, the lowerchamber 52 and the opening 57, and is filled with the fluid. The upperchamber 54 is communicated with the outlet passage 14 through thepassage 55 and is filled with the fluid.

At a position adjacent to the mouth of the passage 55 opening to theupper chamber 54, there is provided an adjusting screw 58 for adjustingthe area of the mouth. The screw 58 can be rotated from outside of thecasing 5l for its adjustment. An auxilliary plate 59 for producingdifferential pressure is provided within the inlet passage 13. Theauxilliary plate 59 is adjustable by rotating an adjuster 60 mounted tothe auxilliary plate 59. At the upper ends of bearings 23 and 25 and thelower ends of bearings 24 and 26, there are respectively providedlabyrinth packings 61, 63 and 62, 64 for preventing leakage of thefluid.

The arrangementof rotors 21 and 22 and shafts 19 and 20 is the same asin the first embodiment described above. Namely, the rotors 21 and 22and the shafts 19 and 20 are vertically disposed, being supported by thebearings 23 and 26 relative to a load applied in a transverse directionand pivotally supported by bearings 29 and 30 relative to a load appliedin a vertical direction. In`this embodiment, the lower ends of theshafts 19 and 20 are tapered in the form of a pivot and are directlysupported by the bearings 29 and 30. However, the construction embodyingthe invention is not limited to this, but ball bearings may be insertedbetween the shafts 19 and 20 and the bearings 29 and 30 in the samemanner as in the first embodiment.

The operation of the flow meter 50 having the above describedconstruction will now be described. When the fluid to be measured entersthe inlet passage 13, the rotors 21 and 22 are rotated due to thedifferential pressure of the fluid between the inlet passage 13 and theoutlet passage 14 produced by the rotational resistance of the rotors 21and 22 during their rotations. The flow quantity differential pressurecharacteristic in this state is shown in FIG. 6. The flow quantitydifferential pressure characteristic when the auxilliary plate 59 forproducing differential pressure is adjusted to a position in which theresistance of the plate 59 to the fluid flowing through the inletpassage 13 is at the minimum is shown by the curve C in the diagram.

Let it be assumed that the differential pressure between the inletpassage 13 and the outlet passage 14 is AP1 when the flow quantity isQ1. The pressure of the fluid in the inlet passage 13 is transmitted tothe chamber 65 in the support member 56 through the passage 53, thelower chamber 52 and the opening 57, whereas the pressure in the outletpassage 14 is transmitted to the upper chamber S4 through the passage55. Accordingly, the fluid pressure in the chamber 65 is equal to thatin the inlet passage 13 and the fluid pressure in the chamber 54 isequal to that in the outlet passage 14. Therefore, the fluid pressure inthe chamber 54 is lower than that in the chamber 65 by AP,.

For this reason, an upwardly acting vertical force is applied to thehorizontal effective area of the shafts 1.9 and 20 and the labyrinthpackings 62 and 64, and the rotors 21 and 22 and the shafts 19 and 20receive the force which pushes them upwardly.

The upwardly acting vertical force f, becomes f1 a-nAPl where,

W1 total weight of the rotor 2l (22) and the shaft Namely, the verticalshaft load applied to the bearings 29 (30) is smaller than the totalweight W, by the force fl produced due to the differential pressure.

If it is desired to further decrease the shaft load applied to thebearing 29 (30), the auxilliary plate 59ffor producing the differentialpressure is adjusted. When the auxilliary plate 59 is rotated by meansof the adjuster 60 by a desired angle, the resistance in the fluidpassage in the inlet passage 13 increases. The flow quantitydifferential pressure characteristic in this state is shown by the curveD in FIG. 6. It will be seen that at the flow quantity Q1, thedifferential pressure .becomes AF2, the differential pressure increasingfurther by (APZ API) by the rotation of the plate 59. The shaft load W2'carried by the bearing 29 (30) in this state is expressed, as in theabove described equation Accordingly, the shaft load W2' can be made avery small value by selecting the effective area a and the differentialpressure AP, at suitable values.

If the lower end portions of the shafts 19 and 20 and the bearings 29and 30 are gradually worn away and the I lower surfaces of the rotors 21and 22 are caused to slide against the upper surface of the lower plate16, the resistance which the rotors receive during rotation increaseswith a resultant increase in the differential pressure AP. On the otherhand, the increase in the differential pressure AP increases theupwardly acting ver tical force applied to the rotors 2'1-and 22.Accordingly, the rotors 21 and 22 receive a force which acts in adirection to push the rotors 21 and 22 upwardly,

thereby separating the lower surfaces thereof away from the uppersurface of the lower plate 16. Consequently, the increase in therotational resistance is suppressed under the influence of thedifferential pressure even in the foregoing state.

In the case wherein the lower end portions of the shafts 19 and 20 andthe bearings 29 and 30 are worn to such a degree that the abovedescribed balance due to the rotational resistance and the differentialpressure can no longer be maintained, threaded portions 34 and 35 arerotated from outside of the casing 5l so that the positions of theshafts 19 and 20 and the rotors 21 and 22 will be adjusted to a heightat which they are properly supported bythe bearings.

While the invention has been described with respect to specificembodiments, various modifications and variations thereof will beapparent to those skilled in the art without departing from the scope ofthe invention which is set forth in the appended claims. v

What we claim is:

1. A flow meter comprising: a casing having an inlet passage and anoutlet passage at both sides thereof; an upper side plate and a lowerside plate provided in said casing and defininga fluid passage whichforms a horizontal flow passage together with the inlet and outletpassages, said upper side plate and the casing defining an upperchamber, and said lower side plate and the casing dening'a lowerchamber; means for introducing fluid in the flow passage into the upperand lower chamber; rotor shafts arranged in a direction vertical to thehorizontal flow passager including the fluid passage and the iniet andoutlet passages, said shafts penetrating through the upper and lowerside plates; rotors xedly mounted on said shafts and having a plane ofrotation in a horizontal plane, said rotors rotating with the shafts inthe fluid passage; an inner housing defining side surfaces of a space inwhich said rotors rotate; thrust bearing mounted on the casing sideunder the lower side plate and pivotally supporting the lower ends ofsaid shafts; radial bearings mounted respectively on said upper sideplate and said lower side plate and supthe lower chamber and portingsaid shafts with respect to a transverse load; a counter sectionprovided on the casing; and means including gears provided in the upperchamber, said means transmitting rotations of they shafts to the countersection, said introducing means comprising a first passage communicatingsaid inlet passage with said lower chamber and a second passagecommunicating said outlet passage with said upper chamber, said shaftsreceiving an upwardly acting vertical force by the differential pressurebetween the fluid pressure in said lower chamber which is equal to thefluid pressure in said inlet passage and the fluid pressure in saidupper chamber which is equal to the fluid pressure in said outletpassage, whereby a shaft load acting in a vertical direction due to theweights of said rotors and shafts is reduced.

2. The flow meter as claimed in claim 1, comprising a resisting memberprovided in said inlet passage of the casing and imparting resistance tothe fluid to be measured which flows through said inlet passage andmeans for variably adjusting the resistance to the fluid in accordancewith its rotated position thereby adjusting the differential pressure ofthe fluid between said lower chamber and said upper chamber.

3. The flow meter as claimed in claim I comprising means for adjustingan area of a mouth of said second passage opening to said upper chamber.l

4. The flow meter as claimed in claim l, comprising a support memberprovided in said lower chamber with a portion thereof being fitted insaid casing and mounting said thrust bearings thereon, said supportmember being formed with an opening for introducing the fluid pressureof said lower chamber into a chamber formed within said support member.y

5. The flow meter as claimed in claim l, comprising labyrinth packingsrespectively mounted on the lower portions and upper portions of saidshafts within said lower chamber and said upper chamber, said labyrinthpackings respectively receiving the fluid pressures in the upperchamber. il ik

1. A flow meter comprising: a casing having an inlet passage and anoutlet passage at both sides thereof; an upper side plate and a lowerside plate provided in said casing and defining a fluid passage whichforms a horizontal flow passage together with the inlet and outletpassages, said upper side plate and the casing defining an upperchamber, and said lower side plate and the casing defining a lowerchamber; means for introducing fluid in the flow passage into the upperand lower chamber; rotor shafts arranged in a direction vertical to thehorizontal flow passage including the fluid passage and the inlet andoutlet passages, said shafts penetrating through the upper and lowerside plates; rotors fixedly mounted on said shafts and having a plane ofrotation in a horizontal plane, said rotors rotating with the shafts inthe fluid passage; an inner housing defining side surfaces of a space inwhich said rotors rotate; thrust bearing mounted on the casing sideunder the lower side plate and Pivotally supporting the lower ends ofsaid shafts; radial bearings mounted respectively on said upper sideplate and said lower side plate and supporting said shafts with respectto a transverse load; a counter section provided on the casing; andmeans including gears provided in the upper chamber, said meanstransmitting rotations of the shafts to the counter section, saidintroducing means comprising a first passage communicating said inletpassage with said lower chamber and a second passage communicating saidoutlet passage with said upper chamber, said shafts receiving anupwardly acting vertical force by the differential pressure between thefluid pressure in said lower chamber which is equal to the fluidpressure in said inlet passage and the fluid pressure in said upperchamber which is equal to the fluid pressure in said outlet passage,whereby a shaft load acting in a vertical direction due to the weightsof said rotors and shafts is reduced.
 2. The flow meter as claimed inclaim 1, comprising a resisting member provided in said inlet passage ofthe casing and imparting resistance to the fluid to be measured whichflows through said inlet passage and means for variably adjusting theresistance to the fluid in accordance with its rotated position therebyadjusting the differential pressure of the fluid between said lowerchamber and said upper chamber.
 3. The flow meter as claimed in claim 1comprising means for adjusting an area of a mouth of said second passageopening to said upper chamber.
 4. The flow meter as claimed in claim 1,comprising a support member provided in said lower chamber with aportion thereof being fitted in said casing and mounting said thrustbearings thereon, said support member being formed with an opening forintroducing the fluid pressure of said lower chamber into a chamberformed within said support member.
 5. The flow meter as claimed in claim1, comprising labyrinth packings respectively mounted on the lowerportions and upper portions of said shafts within said lower chamber andsaid upper chamber, said labyrinth packings respectively receiving thefluid pressures in the lower chamber and the upper chamber.